This invention relates to saw blades for in-line reciprocating hand-held power saws, and more particularly, to such saws useful in demolition work.
Hand held power saws of the reciprocating blade type are used for a variety of tasks. One such task is that of demolition. A power saw of this type is made and sold by Milwaukee Electric Tool Corporation, Brookfield, Wisconsin, under the trademark Sawzall(copyright). Other companies make and sell similar power saws.
The demolition saw blades presently available for use with these power saws, however, are typically provided with cutting teeth on only one longitudinally oriented edge. Thus, if a workman must cut through material comprising components of disparate hardness, for example, wood having embedded nails, the saw blade must be changed or it is likely to break.
Accordingly, it is the primary object of the present invention to provide a saw blade for use in in-line reciprocating hand-held power saws of the Sawzall(copyright) type that will be suitable for cutting through material comprising components of disparate hardness.
It is a further object of the present invention to provide such a saw blade that will have cutting edges comprising cutting teeth adapted to cut through materials of disparate hardness, the teeth being disposed on the opposed longitudinally oriented edges of the main body portion of the saw blade.
It is a still further object of the invention to provide a method of cutting through material comprising components of disparate hardness using an in-line reciprocating hand-held power saw of the Sawzall(copyright) type.
It is a further object of the invention to provide a method of making a replaceable saw blade of the above-described type.
My saw blade comprises a main body portion and a symmetrical mounting portion or shank attached to the proximal end of the main body portion. The shank comprises an aperture disposed on the longitudinal axis of the blade such that the mounting portion can be reversibly received in the chuck of the power saw. The main body portion comprises oppositely disposed generally longitudinally oriented first and second cutting edges that comprise cutting teeth adapted to cut first and second materials of disparate hardness.
My method of cutting through material having first and second components of disparate hardness comprises providing a portable in-line reciprocating power saw having a chuck adapted to reversibly mount a replaceable cutting saw blade. I further provide a saw blade adapted to be received in the chuck. The saw blade has oppositely disposed first and second cutting edges. The cutting edges comprise, respectively, first and second cutting teeth adapted to cut the first and second components of the material. The method further comprises mounting the saw blade in the chuck with the first cutting edge oriented in a manner to cut through the first component of the material and cutting the first component using the teeth of the first cutting edge. The method further comprises cutting the second component of the material using the teeth of the second cutting edge.
The saw blade can be reversed in the chuck to orient the second cutting edge in a manner to cut through the second component of the material. Alternatively, the power saw can be reversed to orient the second cutting edge in a manner to cut through the second component of the material.
My method of making the replaceable saw blade comprises providing a length of band saw blade material comprising a back edge and a cutting edge. The cutting edge includes first cutting teeth adapted to cut a first component of material having a first hardness.
The method further comprises providing a die having a pair of longitudinally oriented sections. The first one of such sections is adapted to cut the back edge of the band saw blade material in the shape of the second cutting edge of a saw blade. The second one of such longitudinally oriented die sections is adapted to cut the desired type of cutting teeth on a shaped second cutting edge of a saw blade, said cutting teeth being adapted to cut a second component of material having a second hardness. The method further comprises placing the length of band saw blade material in the die and closing the die under pressure. The first one of the die sections cuts the back edge of the length of band saw blade material in the desired shape of the second cutting edge of a first saw blade. Simultaneously, the second one of the die sections cuts cutting teeth of a desired type on the previously shaped second cutting edge of a forwardly disposed saw blade.
The length of band saw blade material is then advanced a distance in the die equal to the length of a saw blade and the die is closed under pressure again.